This is the way I do this dish, they come consistently good:
I mix eggs, salt, pepper, and milk (if desired, for me no milk is just fine) in a bowl and whisk very lightly. Too much beating can coagulate the eggs proteins, making the eggs too hard before they are cooked, more appropriate for an omellette than to be scrambled.
I use a cooper (tin lined) fry pan of a small size if it is for two eggs -so they don't spread out too thin- over medium heat.
This probably means that on other type of pan heat should be high.
I rub the end of a stick of butter on the surface of the pan for an even coating and cook the eggs for less than a minute, keeping the eggs in constant motion.
If eggs are stirred, they won't be as fluffy. If eggs are folded, they will have more volume.
One of my daughters doesn't like fluffy eggs, in that case I wisk them harder before cooking and stir them on the pan similar to Caine's description.
The result are denser eggs and much smaller in volume.
IMO, the secret is in using high even heat, the cooper pan helps a lot to achieve this.
"Tell me what you eat, and I will tell you what you are" Anthelme Brillat-Savarin